For the, like, five of you who may remember me, this is not an early April Fool's joke. I have returned to hopefully finish this once and for all.

For those who may not remember, I'm the guy with an unhealthy fixation on the Excelsior who, after creating my own version of a cross section for it ten years ago since all others available seemed wrong to me in some way, decided to begin writing a fully fledged technical manual about it. I'm also the guy who created a cross section of the original Enterprise as a college illustration class project, put up a giant un-watermarked version of it on the internet, and later discovered through the aid of a friend here that it had ended up on the Art Asylum toy box. Highly flattering, if slightly annoying. I would have totally given them a more polished version without the label lines if they'd asked. More on why this is relevant in a bit.

Anyhoo, my last effort on the technical manual can be seen here. My influences were primarily Mr. Scott's Guide to the Enterprise, the Star Trek: The Next Generation Technical Manual, and a naval history book some of you may have heard of called The Essex Aircraft Carriers by Andrew Faltum. I came to believe that Excelsior's virtual omnipresence and apparent longevity provided a unique opportunity to examine various aspects of Treknology that I felt had not been fully explored. I decided to do a book that was half history and half technical manual, the latter written from a 2290s perspective circa Star Trek VI. This eventually diverged into a consideration of the ship's intended scale, which can be seen here.

Previously I had become burnt out on the project, partially due to my own feelings of franchise fatigue and partially because I seemed to keep unearthing more questions and uncertainties with the answer to each question. I am resolved to take this at a slow but steady pace, and finally finish this project. To that end, I am going to treat this as a research project in the most formal sense.

I have outlined a few ground rules for myself, to try to give this some structure.

First, a definition of my concept of canon levels.

Canon - all officially produced series and films; I am ignoring the Kelvin films for the most part, simply because they take place in an altered timeline. (I will say that I do believe the Vengeance is the Kelvin timeline equivalent of Excelsior. Explanation of that later.)

Semi-canon - books, articles, and illustrations or statements made by production staffers

Non-canon - anything else

Now some insight into my thought processes.

In general, I am attempting to avoid stances on extremely controversial topics that might serve to invalidate my work if one of those topics is later answered in a creative way.

It is my intention that what is seen on screen is always automatically canon, unless there is a direct contradiction with other evidence of the same level; in this case, the validity of both must be examined and a compromise made. For example, conventional wisdom holds that the refit Enterprise as seen in Star Trek V does not actually have 78 decks, nor are starship decks generally numbered from the bottom up, and yet we have seen on screen labels indicating that it does.

If semi-canon, particularly in the area of creative intent, contradicts canon, validity and compromise must also be considered.

I am generally avoiding specifically referencing non-canon sources, although I have and will drop in some vague references to them in an attempt to lampshade certain non-canon topics as I deem necessary.

There are a number of key considerations that must be addressed now that I am revisiting this project. Most of these share Treknological concerns with other vessels.

Excelsior size and scale in relation to other vessels
While there is an official semi-canon size given for the Excelsior, that has largely been adhered to by most productions, there is enough ambiguity regarding the model's scaling and design features to leave the ship's "actual" size ambiguous. For this investigation, I have made several assumptions regarding the size of other starships. I have grouped the "known" sizes of major relevant starships into several categories based on my assessment of the certainty of their size.

Certain - the designers and production team were mostly consistent on the intended size, and the portrayal of the vessels' scale on screen is roughly consistent:

Enterprise (refit) and Enterprise-A, as well as derivative models (Reliant, Stargazer)

Enterprise-D, as well as derivative models (Nebula)

Voyager

Enterprise-E ("Nemesis" be damned)

Ambiguous - the designers and production team were mostly consistent on the intended size, but there are details on the models that may indicate a different size

Enterprise (original)

Grissom

Undetermined - the design and production teams appear to have either been in disagreement, or sizing was changed during the construction or appearance of the ship on screen

Excelsior

Defiant

While I do not propose to solve the question of the size of all these ships definitively (I'm not that masochistic) I do hope that at least examining the possibilities will assist with context for Excelsior. I feel that the previous thread on the topic successfully proved that the model makers' intended size for Excelsior was far larger than the later-established production size. Based partly on comments by Mr. Bill George, I believe the original intention, spurred by an ambiguous directive of "bigger than the Enterprise" was probably in the 2000 ft range, double the stated length of the refit Enterprise. This was reduced to 1500 ft by Mr. Nilo Rodis's production scale chart for Star Trek III, which was in turn later used by Mr. Andrew Probert when developing the Enterprise-D and the ships in between.

The real remaining question on this topic really is: which size fits better, and which to I use? Adjusting for model size variance, the larger size works out to around 622 meters. This corresponds fairly well to Mr. Doug Drexler's Enterprise-B cross section (even if there are some other oddities there) and leaves the Excelsior only slightly shorter than the Enterprise-D. However, as I'll explain a bit more later, the secondary hull of Excelsior is likely about 75% hollow, and almost two-thirds of her length is the extremely long warp nacelles, meaning that although she would be almost as long as the Enterprise-D, she is nowhere near as voluminous. I am hoping a re-examination of evidence and other examinations may point me to which "real" size I should use

Structural integrity
Perhaps surprisingly, for me this one ties directly to size. If the Excelsior is actually the smaller size, it's less of a big deal, but if she's the larger size, why would the next ship of the line (Ambassador class) actually be smaller? As mentioned before, the Excelsior's secondary hull is probably mostly hollow and almost two-thirds of her length are made up of warp nacelles.

We know from the semi-canon TNG Technical Manual that Galaxy class ship hulls are "hollow" and "birdlike" in construction, using trusses reinforced with structural integrity field conduits to maintain their shape under extreme conditions such as warp flight. Major systems and habitable areas, including the decks themselves, are essentially hanging inside the hull. It stands to reason that this was not always the way starships were built through Starfleet history.

Fellow TrekBBSer Shaw, partially inspired by several diagrams from the TOS bridge set, posited that the original Enterprise was constructed out of many separate hull pressure compartments, that were then assembled into the primary and secondary hull structures we know. I find this idea brilliant, partly because it explains how an older ship could be built more "conventionally" than the TNG TM way, but also because it provides a great explanation for how the TOS ship could be rebuilt into the refit which has somewhat different proportions; simply disassemble the ship into its constituent pressure compartments, rebuild each compartment, and then reassemble into the new overall shape. I believe that the Excelsior may have marked some sort of transition point in the way Starfleet built their ships, owing in part to the unusual secondary hull "chasm" that I will discuss more in a bit, but as I said the decision I make regarding Excelsior's size may sway me one way or another on the decision of how she was actually built.

Internal arrangement
Convention and various external details allow us to begin to extrapolate the internal arrangement of the Excelsior, but there are still some uncertainties and oddities that cloud matters. For one, again depending on the size selected, the size of the bridge dome(s) seen on the Excelsior may not be large enough to fit the bridge sets inside... and yet convention tells us that the bridge is indeed there.

Warp/Transwarp Drive
The biggest question, of course, is what the heck was the transwarp drive Excelsior was testing? I believe to answer this question properly, warp drive as a whole and the later depictions of "transwarp" drives must be examined. While the concept of warp drive has been mostly fleshed out, in the early days of TOS there was some uncertainty as to exactly how it worked or was powered. There was an early notion of lithium (later dilithum) circuits and an overall general indicaton of dilithium and antimatter pods being some source of power. With later series, the concept was more fleshed out, and the notion of faster "transwarp," sometimes usig conduits and sometimes not, were bandied about, not to mention "quantum slipstream." With ENT, we saw a largely retro version of the TNG-type tech

It is my general conclusion that in the history of Earth and the Federation in the Trekverse, warp power generally followed an evolutionary pattern not unlike our real-world modern combustion engine. Reaction chambers are roughly analagous to cylinders, dilithium "circuits" to spark plugs. Just as in the real world, initially the technology would be crude and limited. As evolution progressed, power would increase by multiplying the number of cylinders (reaction chambers), until the individual reactions became more powerful and efficient and fewer cylinders would again become needed. I believe thie evolutionary undulation can explain the inconsistencies from generation to generation, and how the same basic core design from TMP's Enterprise refit could later power the apparently much faster Voyager.

Now how does all this play into transwarp? Well that is the question.

Anyway, this is just a kickoff. I'm working on both revised timeline and text, plus some perty pictures to share soon. I hope you'll join me for the ride.

I'm going to try to post something at least every other day to make myself keep momentum on this. Feedback is very welcome.

For today, here's my current treatise on how I envision structural integrity systems evolving in the Trekverse. I have a couple of these little treatises that are mostly going to act as source material for the manual, and I'm not yet sure how much of their text I will work into it. I may interject little chapter breaks to address them, similar to what was done in the Haynes Manuals.

Structural Integrity Evolution:

Structural integrity and hull pressure were among the earliest and most significant problems to face all space-faring civilizations. In the early days of Federation shipbuilding, this problem was solved by constructing starships of a series of interlocking, individually reinforced hull pressure compartments.

These compartments were designed in harmony with the ship's overall design, with stress points determining the size and shape of the compartments. Bulkheads and decks played an important part in the structural strength of each compartment, and as a result view ports were kept small and relatively few on early vessels. Even so, the vessels could not withstand the tensions of superluminal flight without the aid of structural integrity field projection. Primitive structural integrity field generators (adapted primarily from Vulcan technology) provided the additional strength needed to maintain ship rigidity at high speeds. These generators were scattered throughout each compartment of each vessel, creating an overlapping and permeating graviton field that actively countered the forces working against the starship under sublight and warp power.

Pressure compartments provided double walls, as thick as the outer hull itself, between each compartment, and with emergency bulkheads and force fields in place could maintain pressure in the rest of the ship even if entire compartments were destroyed. A case study of this can be found in examining the fate of the late Constitution class USS Constellation, which remained still largely inhabitable after being devastated by the so-called "Planet Killer" automated weapon and having several compartments blasted open or destroyed entirely. On a Constitution class starship, inner core compartments comprised the center of the saucer section vertically, and the engineering section horizontally, surrounded by mid and outer core compartments radiating outwards. Other vessels used similar compartment arrangements, particularly after the movement towards modularity that was born from the design of the Constitution class and her sibling classes in the 2240s.

Individual pressure compartments were manufactured separately, sometimes at planetoid surface locations, and then brought into drydock around the ship's skeletal keel and locked together via a series of atomic welds and locking members. This process would begin with the inner compartments and work outwards, in the case of the Constitution with the saucer and engineering sections still separate. Along the way, major systems hardware were installed as needed, although often these were fully or mostly contained within an individual compartment. Once the saucer and engineering hull section assemblies were complete, the two hulls were joined by the addition of the interconnecting dorsal compartments, after which the outer hull plates were laid in place. The result was an extremely physically rigid structure.

A common misconception among technological historians, the Excelsior class was NOT the first ship of the line to use the truss and structural integrity field system that made the Galaxy class possible, but instead was the pinnacle of Starfleet's pressure compartment technology taken to its limits. The requirements of transwarp drive and the Excelsior project both required a large vessel, necessitating an ingenious expansion of the aging pressure compartment technology. Coupled with an experimental version of the modern structural integrity field (but without the large trusses and "hanging" infrastructure that would be the hallmark of later classes) the Excelsior's unusual design was partially a result of the requirements of pressure compartment shapes. The saucer remained fairly conventional in internal compartment arrangement, but the engineering hull was roughly a halved version of the Constitution engineering hull, with the lower chasm an entire compartment to itself. The "humpback" that supported the nacelle pylons was also a result of this. The shuttlebays were an early attempt at a "hanging" structure; although thanks to the variable gravity of a starship in space the fantail bay hung "up" as a superstructure.

The Ambassador class was actually the first ship of the line class to use the modern truss and SIF system and "hanging" compartments and decks, which partially explains the shift towards integrated curves as well as her somewhat "stocky" stature compared to Excelsior. Data from the use of the prototypical SIF fields of Excelsior allowed for this pioneering development, which abandoned the pressure compartment design entirely and rendered the entire starship a hollow shell. Structural integrity field power was transmitted through conductive fibers within the structural trusses themselves, rendering the ships highly rigid. This allowed for an appreciable decrease in overall mass and a very significant improvement in the ability to customize the internal arrangement of a starship, as well as allowing for increased size and numbers of view ports across the outer hull.

The Ambassador design was not completely a success, largely due to the conflux of complicated, experimental systems included in her design including her structural systems. The Excelsior design had proven extremely sturdy, though the rigidity of the pressure compartments caused a characteristic vibration at higher warp speeds. Indeed, part of the reason for the longevity of the Excelsiors was the unusual balance of simplicity and structural integrity in their pressure compartment design, which allowed for a relatively simple disassembly and upgrade process for the class as pioneered on the Melbourne prototype. This made an already extremely structurally stable design also easy to upgrade, giving it an edge on the more complicated, less structurally sound Ambassadors. This is the other reason why Ambassador class starships proved such a rare sight in the second half of the 24th century while Excelsiors were still common. However, the design concepts used in the Ambassador were perfected during the research leading up to the construction of the Galaxy class, and successfully applied to a myriad of other modern starship classes afterward.

For similar reasons to Excelsior, the numerous members of the Miranda class produced also proved easily upgradeable and customizable, extended further by the shape of her pressure compartments and the ease-of-access to her internals provided by the two large aft hangar/cargo decks that allowed limited upgrades without complete disassembly. This also proved true for the largely hollow Constellation class, and the extremely simply constructed and highly modular Oberth class. The Excelsior's "swiss army knife" secondary hull - the large flat dorsal cargo deck doors and the variable use "chasm" - provided a similar ability of limited upgrade without complete rebuild. By contrast, Constitution class ships would be phased out in the early 24th century partly due to the more extensive disassembly required for refits and upgrades.

I am just doing a drive-by at the moment and haven't dived into the above comments yet, so my apologies if you've already covered this, but regarding the Deck 68, etc of "ST5" on Enterprise-A, the author of "Mr. Scott's Guide To The Enterprise" speculated that some of the turbolift shaft doors were taken from Spacedock and not repainted with the correct level numbers. That explanation made more sense than trying to shoehorn 70 some decks into a 23-deck ship. The correct doors probably weren't due until Tuesday...

I am just doing a drive-by at the moment and haven't dived into the above comments yet, so my apologies if you've already covered this, but regarding the Deck 68, etc of "ST5" on Enterprise-A, the author of "Mr. Scott's Guide To The Enterprise" speculated that some of the turbolift shaft doors were taken from Spacedock and not repainted with the correct level numbers. That explanation made more sense than trying to shoehorn 70 some decks into a 23-deck ship. The correct doors probably weren't due until Tuesday...

Click to expand...

Hey man, glad to see you still around! I totally agree there are a number of fully plausible explanations why those numbers were there. To me, this is just one of those cases where you look at the screen and go "nope."

Alright guys, as promised here's a treatise of where I'm thinking of going with how I'm going to depict warp and transwarp development. You'll notice there's a placeholder for the chemical name of dilithium, which I know I've seen somewhere but haven't been able to dig it up. I also am unsure about referring to the pre-TMP warp drives as "circumferential" and warp drives from TMP onward "linear."

Hope you enjoy. Please let me know your thoughts. Next up will be my revised timeline.

Warp Evolution:

Throughout recorded history, with some notable exceptions, most civilizations have been found to utilize the same basic principles of what the Federation calls "warp drive": a powerful reactor, usually in the form of a matter/antimatter annihilator mediated by dilithium (the longer form of the crystal name is the forced-matrix formula 2<5>6 dilithium 2<:>1 diallosilicate 1:9:1 heptoferranide) crystals, generates power that is absorbed by coils or generators to "warp" space around a ship, pushing and pulling the continuum around the ship in propulsive force, with the net result that the vessel seems to travel faster than the speed of light.

Early Earth vessels followed this very basic archetype. Zefram Cochrane's original reactor, which set the standard for the Federation and much of the Alpha Quadrant, was little more than a "matter/antimatter collider." Matter (in the form of deuterium) and antimatter (in the form of antideuterium) were hurled at one another via magnetic constriction from opposite directions, converging at a reaction chamber containing a small, single dilithium crystal. The resulting annihilation reaction, when focused through the dilithum, produced a highly energized plasma. This plasma could not only power all systems on board, but produced the massive energies needed to energize the asymmetric warp coils that would generate the warp field and propel the ship.

This basic reactor and engine format changed little in the succeeding centuries. Two main problems soon emerged with trying to improve the design: reaction control and dilithium crystal quality. Ships constructed after Cochrane's prototype used a somewhat more refined warp reactor which historically is now referred to as a circumferential warp drive(?). Matter and antimatter were injected into an a dilithium "circuit," making contact at roughly the same time with one another as with the dilithium. This plasma swirled around the crystal circuit several times before passing into magnetically insulated power transfer conduits.

The result was a relatively unrefined annihilation that left behind an impure plasma. During this era, warp reactions were considered inefficient and difficult to regulate, sometimes referred to "dirty." Controlling the acceleration of the reactants and speed of the reaction proved problematic. If the reaction ratio was misaligned in favor of the antimatter flow, residual antimatter would be left in the reaction chamber and would annihilate part of the plasma; if the ratio favored the matter, the residual plasma would be less energetic overall and maintain energy levels for less time. Beginning with the mid 2150s, warp reaction assemblies passed plasma through "accelerators" which boosted the quality and power of the plasma via the injection of small amounts of additional antimatter to trigger a series of secondary reactions, before ultimately reaching the warp coils.

Another part of the "dirty" reaction issue was the quality of the dilithium crystals themselves. In the Sol System, dilithium (once sometimes imprecisely abbreviated as "lithium") was initially discovered in meteorites found in Antarctica, and then later mined on the moons of Jupiter and in the asteroid belt. The discovery made the development of warp drive possible, as no previously established power source was adequate. Initially, some early scientists believed that dilithium actually generated the power that infused into the plasma, but it was later found that it merely channeled the power of the annihilation reaction into the tuned plasma without annihilating the plasma itself. The shape of the crystals proved to be important, and later mining operations "cracked" them to form the necessary crystalline chemical and physical structures.

By the mid-2240s, new Starfleet warp reactor designs combined several sets of dilithium circuits into a compound reactor setup, eliminating the need for accelerators. Plasma passed through initial dilithium control circuits, and then was cycled through several more times until it reached sufficient energetic levels to be usable for warp power. In the case of Constitution class, four dilithium circuits were required to fully power the ships and their warp engines, and another control circuit was later added to the loop, partially to regulate the other reactions and partially to energize plasma for the ship itself. When this main control crystal was removed from its chamber, the other reactions would lose power on each cycle and soon lose power altogether.

Aboard a starship using the compound design, the power level generated was largely determined by the quantity and length of its dilithium circuits, which tended to use an undue amount of space aboard ship. Additionally, since the design continue to evolve in the field after its initial installation, such as with the addition of the control circuit, the setup grew to be complicated and cumbersome. Engineers began designing a replacement.

Transwarp Evolution:

"Transwarp" is a catchall term for "engine capable of surpassing warp" applied to several disparate designs over the course of history. These designs primarily share the fact that they surpass the known warp barriers in some way.

In the case of Excelsior, transwarp specifically referred to a new type of drive that would push a ship so deeply into subspace that it would leave normal space altogether, travelling through subspace for a predetermined amount of time before re-emerging at its normal space destination. Due to the time differences between subspace and normal space, greater distances could be traveled via the relative time of the crew. Engineers believed that a sufficiently powered engine of this type could act as a "jump" drive, instantaneously transporting the ship anywhere in the known universe. Hence, the term "infinite velocity" was coined, although the theory of a jump drive would never be achieved and the term would become something of a historical misnomer and lead to misunderstanding among many historians.

As part of the project, engineers designed the "linear warp drive," (?) which went back to the more direct basic pattern of Cochrane's collider model with the revision of multiple dilithium crystals and an overall "swirl" design wherein the intermix chamber was a long cylinder, lined with dilithium at strategic points. Matter and antimatter were channeled into the chamber along parallel magnetic constriction lines and released in a controlled manner. In this design, rather than timed waves of annihilation reactions along a circuit, the annihilation reaction was occurring nearly constantly throughout the entire system. Similar to the previous design, plasma potency was somewhat determined by the number of segments in the intermix chamber cylinder but overall efficiency was better and the reactions were easier to control.

The initial design of this engine was applied to the refit of the Constitution class, where one of the first prototypes of the swirl chamber was installed for shakedown, even as the Excelsior's construction was barely underway. Several refinements to the Enterprise design were made along the way that were applied to the construction of Excelsior. This basic design was soon applied to all ships in the fleet, and later this paradigm would eventually form the basis for the modern warp drive that proliferated throughout the 24th century. Though the "transwarp" drive utterly failed to work as intended, never pushing the ship into subspace as designed, the performance it delivered was nonetheless revolutionary.

Nice to see continued progress! I personally disagree with several points of your warp theory but I won't bother to enumerate them. This is your project from your own headcanon and I look forward to seeing exactly where you go with it.

By the way, I'm not sure if this is what you're looking for, but the TNG Technical Manual (Sternbach and Okuda) on page 60 has the following sentence regarding the technical name for dilithium:

The longer form of the crystal name is the forced-matrix formula 2<5>6 dilithium 2<:>1 diallosilicate 1:9:1 heptoferranide. This highly complex atomic structure is based on simpler forms discovered in naturally occurring geological layers of certain planetary systems.

Albertese! Nice to see you. Thanks for the kind words. You are absolutely welcome to post your disagreements with my warp theory if you'd like to, but I also appreciate your intent in not doing so.

And that is EXACTLY what I was thinking of! Thank you so much. I was having a hard time remember which book it was in. Too many on the shelf.

Here's something that I'm definitely looking for some feedback on... the timeline. I have made some adjustments since I've last sared it with you, partially fueled by recent readings of The Autobiography of James T. Kirk (as well as The Autobiography of Jean-Luc Picard.) Reading both of these definitely helped inspire me to pick this up again, as well as made me question a few of my previous assertions.

See if you can spot the changes.

2245

Enterprise and other first block Constitution class ships launched.

2255

Second batch Constitutions launched

2261

Dr. Eugene Wesley makes 10-domain warp theory discoveries.

2262

Transwarp Development Project work begins; group is called the 'Excelsior Group'

2266

Starfleet Command begins to see the need for a new, well-armed, multi-purpose advanced starship to supplement and eventually replace the aging Constitution class; design project is called SV-20. Meanwhile, design work begins on a total refit for the Constitution class.

Enterprise concludes her historic first 5-year mission under James T. Kirk; Starfleet announces fleet-wide modernization and revitalization refit plans for vessels ranging from the Constitution class to the Miranda class.

SV-20B design submitted.

2271

Federation Council and Starfleet review and approve TDP to be included on SV-20.

2272

SV-20C design submitted.

V'Ger incident

SV-20D design submitted.

2273

Starship Enterprise begins second five year mission of exploration under James Kirk.

2274

ASDB engineers backburner the radical idea of an 'explorer' type starship to focus on the Excelsior.

SV-20E design submitted and approved.

2275

Excelsior name and designs finalized, approved. Starfleet places orders for six ships, with the prototype to begin immediately, followed sequentially by two more.

Construction of Starship Excelsior begins at San Francisco Fleet Yards. Other components under work include the transwarp core at Jupiter Station, transwarp nacelles at Copernicus Yards, Luna, and additional components at Utopia Planitia.

2277

Excelsior frame construction underway.

Enterprise returns from her second five year mission under James Kirk.

Starship Enterprise finally retired after damage in a battle with the renegade Khan Noonien Singh. Enterprise is shortly stolen and Captain Scott sabotages Excelsior to prevent pursuit; results in two months of refit for Excelsior.

Excelsior is trapped idle in dock during the Whalesong Crisis. For saving the Earth, Starfleet rewards James Kirk by renaming the last production Constitution-class ship U.S.S. Enterprise 1701-A, and subsequently change the second Excelsior’s name to Ingram. The next Enterprise is scheduled for construction and launch by 2294, to coincide with the current vessel’s projected date of decommissioning and several of the senior staff's scheduled retirement.

2285

The Enterprise undergoes a six month shakedown cruise, followed by a month’s refit, and afterwards embarks on a new five-year mission.

Transwarp experiments are finally deemed a failure after attempts with three sets of nacelles and two separate transwarp cores. Rather than scrap the costly and otherwise successful Excelsior, Starfleet makes the decision to refit her with conventional warp drive. Construction begins on the next two Excelsior class ships, and commissions are issued for four ships in total. Many in Starfleet consider these decisions dubious at best.

2286

Excelsior re-launched and undergoes second shakedown, certified for duty.

U.S.S. Ingram is launched.

2287

Captain Styles begins a three year mission aboard Excelsior.

2289

Hikaru Sulu joins Excelsior as first officer.

Hikaru Sulu is promoted to captain of Excelsior after Styles is killed. He selects Lt. Cmmdr. Janice Rand as his communications officer.

2290

Excelsior begins new three-year mission in Beta Quadrant 'cataloging gaseous anomalies,' which is really an excuse for increased presence near the Klingon and Romulan empires.

Construction proceeding on the next Enterprise, including several upgrades designed to cure the Excelsior of particular design quirks and expand her capabilities as an explorer.

Yortkown begins her first mission

2291

Admiral Cartwright is replaced as CinC by Admiral William R. Smillie, as Cartwright's militaristic thinking falls out of favor with the Federation Council.

2293

Klingon moon Praxis explodes; Khitomer incident.

Enterprise-A returns to Earth and is decommissioned.

Excelsior returns from her second three year mission and undergoes refit.

The Enterprise-B is commissioned; James T. Kirk lost on maiden voyage, presumed dead.

2295

Excelsior and Enterprise-B are launched on five-year missions. Construction is proceeding on the final of the first six Excelsiors; orders placed for six more, to then be followed by another dozen.

2300

Fourteen Excelsior class starships are in service.

2310

Ambassador class design work begins.

2311

Tomed Incident; Enterprise-B present.

2315

Prototype U.S.S. Mediterranean launched.

Ambassador class design finalized; construction soon commences

Hikaru Sulu is promoted to Admiral and hands command of Excelsior over to Leonard James Akaar..

2316

Prototype U.S.S. Shelley launched.

2318

Prototype U.S.S. Medusa launched.

2322

Prototype U.S.S. Ambassador launched.

2325

Excelsior undergoes a major refit and modernization.

First contact between the Federation and the Cardassian Union. Peace overtures from the Federation are met with resistance by the Cardassians, who perceive the Federation's colonization efforts near their territory an effort to undermine their claims on resource-rich planets. Multiple border conflicts ensue in later years.

2331

Enterprise-B lost in the line of duty.

Fleet-wide refits are implemented to the Excelsior class after the success of those installed aboard Excelsior in 2325.

2336

Launch of the Enterprise-C from McKinley Station in Earth orbit.

2344

Enterprise-C is lost defending the Klingon outpost Narendra III from Romulan attack.

2347

Cardassians massacre colonists on Setlik III, and engage Federation starships dispatched to defend the planet; first of Cardassian Wars begin.

2357

Prototypes U.S.S. Galaxy and U.S.S. Nebula launched.

Starfleet begins initiative to design modern Excelsior refit, culminating with the construction of the U.S.S. Melbourne from a combination of new and spare parts.

2360

U.S.S. Melbourne launched.

2364

Launch of the Enterprise-D at Utopia Planitia.

2366

Open hostilities end between the Federation and Cardassia.

First official contact with the Borg.

2367

Hostilities are renewed between the Federation and Cardassia.

Battle of Wolf 359; Excelsior not in attendance only by fortune of circumstance.

2370

The Federation-Cardassian Treaty is finalized, and the DMZ formed.

2371

Lakota experimental tactical refit program begins.

2372

Lakota refit program deemed unsuccessful after the Lakota performs unimpressively in battle with the U.S.S. Defiant.

U.S.S. Excelsior reassigned to duty in Sol System after the death of former commander Hikaru Sulu.

2373

Outbreak of Dominion War sees Excelsior class ships forming the backbone of Starfleet's combat groups. The ships fight valiantly, but many are lost.

2374

U.S.S. Excelsior is attached to Third Fleet guarding Earth during Dominion War.

2375

Starship Excelsior and several other ships successfully repel a Breen invasion of the Sol System.

The end of the Dominion War sees the decommissioning of many heavily damaged Excelsior-class ships.

2383

U.S.S. Excelsior retired to Fleet Museum on the occasion of her centennial.

The Sovereign-class U.S.S. Excelsior is launched from the San Francisco Fleet Yards.

This is how I'm considering the internal arrangement for the newly 622 meter Excelsior, using a few elements from the previous version of the cross section. The set of drawings will probably be black and white, but eventually I will also do a color MSD. I am currently in the middle of an analysis of supposedly what was on what deck according to the production art from Generations and VGR's "Flashback." More on that to come.

The warp core as currently represented will "resemble" the TNG core since that was what was shown in TUC, although the "actual" function of the core will be of the swirl type. I have positioned it to line up with where the larger, original deflection crystal was.

And before anyone notices, the labels are mostly wrong. The drawing has changed so much since those were created that some of them point to entirely the wrong spots.

Without fully delving into the logic behind why I like the 622 meter size for Excelsior, here's a little math to explain how I arrived at the 622 meter figure. You can delve into it fully in the size thread linked in my OP.

Yes, I actually have some generalities mentioned in the main history text for the manual that I should pin down in the timeline.

Basically, there were several blocks about 5-10 years apart, then a continual production line in the late 2340s that ended when some spare parts were produced. (Some of these spare parts became the U.S.S. Melbourne.) The thought here is that Starfleet was convinced they were about to have an all-out war with Cardassia and didn't want to dedicate themselves to large-scale Ambassador class production.

I'm also in the process of taking a hard look at the actual schematics and deck placement. I'm not entirely happy with either and both are legacy from the last time I took at stab at this.

I really want to come away with the most accurate schematics I possibly can. The main reason for this is I want to settle generally on the center-line cutaway and general deck arrangement at the same time, so when I do the deck plans they come naturally and are as reliable as possible. Those damn portholes on the upper section and the "upper level" of the saucer rim kill me every time I think I'm happy with how the decks line up.

Part of the issue here is that there seem to very clearly be 15 decks worth of height from secondary hull "flat top" to the keel, and I need to figure out how this scale applies to the rest of the ship. I have waffled between all decks being one height and different heights in the saucer/neck/superstructure/secondary hull a few times. With the overall length fixed at 622 meters, I can try out different deck heights and see how they look. Unfortunately, the 15 decks thing I mentioned earlier would be neither 9 ft nor 12 ft... more like 10. But maybe that's ok.

I'll have to settle for a lack of perfection, most likely, but as close as I can get is fine with me. After all these years, I think I need to just answer as many questions as I can.

My solution for matching deck heights to window rows (on my TOS Enterprise deckplans I've been working on on and off since more than a decade ago) has been to allow for the possibility of decks not being of uniform height, or even uniform levels.

In TOS this is totally justified, for instance, the Emergency Manual Monitor Room floor was only about five and a half feet above the floor of the Main Engineering deck. For me, this absolutely allows me to have occasional decks that are staggered at half heights. Having these half decks nearer the outer edges of the hull lets you even respect the cross section MSD graphics if you feel beholden to that sort of thing.

Having the interior built out of Hull Pressure Compartment blocks makes it even easier to justify staggered deck heights. The level floor need only be in a given compartment and a short flight of steps or a ramp or ladder can connect the adjacent sections.

(I figured out the Hull Pressure Compartment thing on my own before Shaw ever posted his thinking. Though, I must admit that I liked his take on it so much that I adopted most of it into my own plans. The beauty of this board is the community of guys who's ideas can all percolate together.)

You mentioned above The Autobiography of James T. Kirk. I recently finished that and loved it. I thought it had a great explanation for why this crew was stuck together for 30 years, and made a lot of the unconnected points of data about Kirk and the show in general flow together that I've adopted it into my headcanon almost whole cloth. Haven't read the Picard one, but I'm a little curious.

Well I'm delighted you're back and have resumed this project - always a fascinating read!

I'm totally on board with the 622m ship, there seem to be no drawbacks as even at that length the ship is still mostly warp nacelle and empty engineering hull. The larger dimensions are still significantly less volume than the Enterprise-C. Otherwise a <500m Excelsior feels ridiculously small.

I've a few disagreements with your timeline, but nothing too drastic. For example, I wouldn't have the Enterprise-B lost in battle. My feeling is that the loss of the Enterprise-C with all hands was such a traumatic and unique event that it was another twenty years before Starfleet felt ready to reuse the name.

My head canon is that the Lakota is actually the Enterprise-B, which was mothballed some time just before the USS Ambassador was launched. She was later reactivated and recommissioned as the Lakota. My feeling is that the Enterprise/Lakota was the one and only example with the additions to the hull, because they weren't any use in practice. I'd expect to see more examples otherwise, such as the Repulse which is another early Excelsior.

Love the rest of it - especially Excelsior herself lasting to her centenary! She's mentioned in TNG after all.

I'm guessing all those earlier SV-20 concepts might be the Excelsior study models?

It's said in the workshop manual which I thought they said was canon that the Enterprise-B disappeared in 2329 so the Lakota can't be the B. Also the USS Okinawa was said to also look like the Enterprise-B.
One of the problems is the fact that people call it Excelsior refit which makes people wonder why they don't all look that way in the 24th century. The Enterprise-B design is a variant of the Excelsior class, It was designed to do something the standard design doesn't or at least doesn't do as well which is why the Excelsior herself never got this refit and there only seems to be a few of the variant design. It's the same as Sisko's Saratoga which is a variant of the Miranda class.

Albertese - I like your solution for the deck heights. I think the cutaway for NX-01 and Mr. Jefferies' cutaway for the original Enterprise fit this idea nicely. However, I'm trying to avoid it since looking at Mr. Probert's deck alignment for the refit Enterprise seems to only really have two heights of deck, with the saucer decks at 9 ft and the engineering hull decks at 12 ft.

Fortunately, I've made a little process with the Excelsior. While I don't have anything to show yet, it looks like I"m going to land with the saucer and engineering hull having two different deck heights, although not 9 ft and 12 ft as Mr. Probert did.

Tomalak - well if it isn't my second favorite Romulan! So glad to see you. As trekfan39 notes, I did get the idea of the Enterprise-B being lost from the Haynes manual; I believe they got it from somewhere else though I don't remember where.

While I do classify the Enterprise-B version a variant and think there must be some logical reason behind it, I have indeed struggled with justifying it and the idea of the Enterprise and Lakota actually being the same ship isn't an awful one. And you guessed correctly - the study models and SVs for the Excelsior design do line up. Thanks for the support!

I hoped to have some progress on my deck placement to show today, but work got in the way. Instead, this seems like a good place to start with the end - in this case the appendices in which I discuss the technology and variants of the class. Like the history section of the manual - and unlike the bulk of the technical section - the appendices are written from a 2383 perspective.

There are a few assertions in here that fly in the face of canon a bit, and a few things that I'm not entirely happy with. I also haven't revised the dimensions presented yet to fit the new 622 m ship. There is also a final appendix planned that will give a summary of the more notable members of the class - basically any that we saw on screen during the series.

I look forward to your thoughts.

Appendix A: Evolution, From Food Slots and Transwarp to Replicators and Holodecks

All classes of Starfleet ship are originally designed with future upgrades and expansion in mind, with scheduled refits following each mission, and major overhauls scheduled typically every other mission. The typical expected service life of a twenty-third century Starfleet ship ranged between twenty and forty years depending on several variables. Many ships, such as the Oberth and Miranda classes, exceed their projected service career, while others are retired early. Nonetheless, few engineers could have imagined the unforeseen longevity and proliferation of the Excelsior class, which was once deemed an engineering failure. In 2383, the Excelsior will have been in service for one hundred years. Despite the high attrition rate seen in the Dominion War, Starfleet will continue to have at least one hundred Excelsior class ships in service for the next twenty years, the class then seeing service across three centuries. As the years since their commissioning have passed, the ships have independently evolved in such a way that no two are precisely alike.

Starfleet engineers have long studied the ingredients of the Excelsior class's success. One is certainly the modularity inherent to the design. As a result, ships with even their entire warp pylon assembly sheared off have been almost seamlessly repaired with relatively little difficulty. In addition, new primary hulls could be constructed and swapped relatively easily with those of existing space frames, providing much-needed upgrades to command and control systems while retaining engines that still functioned adequately. In some cases, the converse was true; new engines replaced tired ones on ships with perfectly serviceable primary hulls and command systems. On one occasion, a ship was rebuilt from only its secondary hull and neck intact was rebuilt and put back into service using scavenged parts from a surplus depot.

Thus is illustrated another ingredient in the success and longevity of the class: their proliferation. The shear number of Excelsior class ships launched became an asset. During the early twenty-fourth century, the combined success of the design and ultimately unfounded fears of war eventually led to the construction of an unprecedented number of Excelsior class ships. As older ships were decommissioned, their parts could be scavenged and used to repair newer ships. This proved instrumental during the Dominion War, where Starfleet quickly found itself needing more starship than it had. Decommissioned Excelsior class starships were refit and recommissioned, some with crews of only two hundred or less and under the command of mere lieutenant commanders. In some cases, Excelsior class parts found in surplus yards were combined to build entirely new ships, some of which couldn't even be strictly described as Excelsior class. Less extreme combinations include the mix-matching of original and Enterprise-B type variant hulls and engines, while other combinations entirely negate the secondary hull or mount an odd number of engines.

Following is a summary of the original production schedule of the entire Excelsior class, followed by a summary of refits and upgrades performed throughout the class's lifetime. The refit summary outlines when specific technologies were introduced to the Excelsior class, and whether these introductions were pioneered on specific vessels.

Over the past one hundred years, the Excelsior design has been modified as technology has advanced. A number of specifically unique variants have emerged as members of their own subclass through the class's history. Some are only one-off experimental vessels, while others have grown into a full production class.

Ingram Variant (2289)

The U.S.S. Ingram was the second Excelsior class starship built, and is technically considered its own class. Originally slated to become the next Starship Enterprise, NCC-2001, the Ingram was renamed after Starfleet decided to honor James T. Kirk and his senior staff for saving Earth during the Whalesong Crisis by renaming the last production Constitution class ship U.S.S. Enterprise, NCC-1701-A. Therefore NCC-2001 was renamed U.S.S. Ingram. The Ingram was only at an initial construction stage when doubts began to emerge about the success of the Excelsior’s transwarp tests, casting doubts on the entire class. As a result, Starfleet CinC Admiral Cartwright authorized modifications to be made to the design of the Ingram to try to give the Excelsior class hope in the event that the transwarp project failed. These modifications shifted the purpose of the Ingram towards a combat-oriented role as what was termed a ‘space control ship.’ In outward appearance, the Ingram was still obviously based on the Excelsior class design. The interconnecting dorsal was shortened for a more shallow profile, two additional shuttle bays were installed on the secondary hull superstructure at the ship’s aft end, and the warp pylons became wings, mounting directly outward from the secondary hull with phaser cannons mounted at their tips, akin to the Miranda class. Overall dimensions were slightly different from the Excelsior, <dimensions will go here>

Technologically, however, the Ingram shared more in common with the Constitution refits than the Excelsior. It is that fact that would ultimately play a key role in her undoing. The Ingram was launched in 2289 and proved adept and her target roles. By that time, however, the Excelsior had already proven her design, minus transwarp, was sound and had completed a refit to enter service. After Admiral Cartwright, the primary champion of converting the Excelsiors to a more combat-oriented role, was replaced as CinC and later disgraced in the plot to assassinate Klingon Chancellor Gorkon and ignite a war between the Federation and the Klingons, supporters of the so-called ‘armament doctrine’ dwindled. It was felt in retrospect that Cartwright was championing the Ingram and ships like her in anticipation of the war he was planning. With no other real need for the class, and a following concession to decommission all Starfleet battleships in the peace talks with the Klingons, the few Excelsior class ships that were built to Ingram subclass specifications enjoyed very short service careers as quayside queens. Ingram remains an oddity in the annals of Starfleet shipbuilding, and the testament to the turbulence of the time in which she was built.

Enterprise-B Deep Space Variant (2293)

The decision to make the Enterprise-B an Excelsior class ship was, at the time, widely considered controversial. Many traditionalists felt it the class had yet to prove itself, and pointed to what they considered serious flaws in the design, including the ship's poor impulse maneuverability and susceptibility to 'warp turbulence.' A major lobby called for the ship to be of the Constellation class, which they felt was somehow more in keeping with the tradition of the previous ship. Other groups called for the creation of an entirely new design. Starfleet compromised, by keeping the new Enterprise an Excelsior class ship but making design modifications to the ship though it was already under construction.

The design of the warp nacelles was modified, adding a new ramscoop assembly and special fins that were designed to reduce subspace drag on the ship and hopefully reduce the effect of warp turbulence on the ship. A major criticism of the Excelsior design was that it maneuvered poorly at sublight, and two additional impulse engines were added on either side of the main impulse deck. These twin engines tested forerunners of the modern impulse driver coil, which has come to be a standard part of modern impulse engines. (Modern refits to older Excelsior class ships incorporate small-scale modern driver coils in their regular-sized impulse engines.) Scientific systems were also greatly improved and refined. The design of the main deflector was modified, and twin hull protrusions were added to either side of the secondary hull, containing additional science labs and sensor systems. Included among these systems were special sensors designed exclusively to detect cloaked ships, a decision the engineers felt was vindicated by the discovery of a Klingon bird-of-prey that could fire while cloaked just prior to the ship’s launch. Rumors abounded at the time of her launch that the Enterprise-B was also equipped with a fully capable prototype Federation cloaking device, retro-engineered from the Klingon bird of prey captured by Admiral James T. Kirk in 2285. Relevant documents remain classified to this day, so the cloaking device rumors remain only unsubstantiated rumors, which many historians consider dubious at best. Overall dimensions of the Enterprise-B were slightly increased by the addition of fins to the warp nacelles, and were as follows: Length, 469.05 meters; Beam, 177.21 meters; Height, 75.93 meters.

As a result of these modifications, the Enterprise-B was externally an entirely different ship from the Excelsior, but in truth remained in essence the same ship. The modifications to the design were, while not unsuccessful, not particularly beneficial either. The attempts to decrease the amount of warp turbulence that the ship underwent were marginal at best, and Starfleet determined that the net gains were not cost-efficient enough to build them on every ship of the class - only those designed for specific, long range or high speed deployments. Eventually, Starfleet engineers were able to make minute refinements to the design of the ship's warp coils that reduced the drag significantly. The additional impulse engines proved redundant by the time the modern impulse driver coil was invented and the standard impulse engines could be redesigned to accommodate them and provide better handling. The Enterprise-B served a long, successful service career, and nearly a dozen more ships of the variant type were produced, but the results of the design were inconclusive, and ultimately rather unnecessary.

Mediterranean Class (2315)

The Mediterranean class began as a design experiment in the earliest part of the 24th century. The engineers at the ASDB were well aware that the Miranda class was more than fifty years old, and while it fulfilled its secondary support and service roles, it could not last forever. Therefore, the ASDB designed a similar vessel based on elements of the Excelsior class, including the saucer and nacelles.

The design resembled an Excelsior saucer mated to a small pod with nacelle pylons extending to either side. A shuttle bay was added to the saucer, just ahead of the bridge module as an extension of the upper deck platform. Consequently, much of the upper saucer layout was completely re-worked. The lower pod mounted twin torpedo launchers fore and aft, reminiscent of the Miranda's 'roll bar.' The design initially employed standard LN-72 warp nacelles as found in the Excelsior class, but this quickly changed as the warp coils were redesigned for greater speed at the cost of stability. The first ship of the class was launched in 2315 as NX-20481. The class initially only went into limited production. However, as relations with the Cardassians deteriorated, the class produced several blocks. The final ship of the class, Centaur, was launched in 2349 to coincide with the discontinuation of Excelsior production. Overall dimensions were: Length, 381.87 meters; Beam, 320.16 meters; Height, 78.54 meters.

The class was never a particular Starfleet favorite, and ultimately less than 100 ships of the class were built, many of which were retired or transferred to civilian Federation use as refits for the Miranda class proved more cost efficient than expected, and the Nebula class was introduced to fill many of the same roles. Many ships of the class, including the Mediterranean herself, were retired by 2357. Remaining ships found use as couriers and cargo ships, as their impressive performance designed for scouting mission profiles provided invaluable speed. With the onset of the Dominion war in 2373, and Starfleet in need of ships, many of them, including the U.S.S. Centaur, were recommissioned with upgrades and continued to serve in limited capacities for several years after the war's end.

Shelley Class (2316)

Since the end of the Earth-Romulan War of the mid 22nd century, Starfleet has eschewed the use of assault fighters in combat scenarios. Modern starship technology renders fighters essentially useless against large cruisers protected by energy shields. Most fighters are simply incapable of piercing the shields of larger ships, even in groups, before being isolated and destroyed. However, there remains the occasional need for small fighters, in raids or other missions where speed and maneuverability are preferable to sheer firepower. Therefore, Starfleet maintains limited numbers of through-deck cruisers such as those of the Shelley class. Through-deck cruisers are not simply carrier ships; they are also supply ships intended to be a key part of Starfleet combat divisions. As well as possessing expansive hangar decks, they also have large cargo bays for materiel and supplies. They are also often used to land ground forces when needed.

Like the Mediterranean class, the Shelley class underwent initial design work in the early 2300s, based on the success of the Excelsior program. The initial design rearranged the basic Excelsior elements, placing the interconnecting dorsal and saucer at the aft end of the secondary hull, and shuttlebay two at the forward end, allowing for direct interconnectivity between shuttlebays one and two. Almost all of the secondary hull volume was dedicated to hangar decks. The warp nacelles were held off pylons connected to the port and starboard edges of the saucer. This allowed the saucer/nacelle assembly to separate from the secondary hull and still retain full flight capability. The reuse of modular Excelsior components allowed for inexpensive production.

The first ship of the class, U.S.S. Shelley, NX-23410, was launched in 2316 and performed beyond expectation in initial flight trials. In fact, the ship was deemed too powerful. With her secondary hull essentially empty, the large LN-72 nacelles first equipped to the Excelsior class were more powerful than was necessary. Therefore, on later models Starfleet experimented with multiple engine configurations using LN-64 Mod 3 Linear Warp Drive Units, standard on Constellation and Miranda class ships. These configurations proved much more successful than the original. Some of these last ships produced were of the variant Curry class. Overall dimensions of the U.S.S. Shelley were: Length, 383.41 meters; Beam, 195.64 meters; Height, 148.50 meters. For subsequent ships, lengths varied but were approximately: Length,

Shelley class ships saw moderate duty in their service careers, particularly in the 2340s and 2350s in conflicts along the Cardassian border. Most were retired by 2355 as newer ships supplanted their mission roles, but the onset of the Dominion War saw many refurbished and returned to duty, carrying full wings of fighters in their bays, as well as other reconnaissance and repair vehicles. Most of the ships to survive the war were decommissioned, but a few continued to serve in limited roles for several more years, particularly on relief missions into the Cardassian Union. A few were sold into civilian use as freighters.

Medusa Class (2318)

As the size of the Federation gradually increased, Starfleet became concerned with its ability to rapidly deploy vessels to troubled remote areas. Most of its ships were simply inadequate to the task, having been designed when the Federation was still relatively small; scouts were fast enough, but lacked the range and firepower to be of any real use in a firefight, while cruisers had the firepower but lacked the speed. The Constellation class was one of Starfleet's answers to this problem. Originally conceived as a supplement to the aging Constitution class, the Constellation, with its four nacelles and relatively low mass, could generate a highly efficient warp field and was capable of reaching distant locations more quickly than most other ships, while retaining sufficient size and firepower to be classified as a cruiser. It was therefore classified a 'deep space cruiser.' As well as its interdiction capabilities, the limited run of the Constellation class was able to perform long range exploratory and reconnaissance missions with ease, greatly lightening the workload of the Constitution class.

By the dawn of the 24th century, the success of the Constellation and Excelsior classes spurred the ASDB to develop a new deep space cruiser using the basic components of the Excelsior class which they tentatively called the Medusa. The initial designs of 2310 called for a four-nacelle ship similar to the first Excelsior pathfinders, but performance concerns forced the engineers to reduce the mass of their design. Ultimately, the fourth nacelle was dropped, and the remaining three reorganized around an enlarged Excelsior saucer and extended aft section. Three-nacelle starships were relatively unpopular within Starfleet, as their warp fields were powerful but difficult to regulate. Still, the three-nacelle configuration had been successful with the Federation class and the ASDB decided to go ahead with it. The two dorsal warp nacelles sat on the traditional warp pylon support (albeit relocated to a mounting point atop the lengthened impulse deck) while the lower nacelle was supported by twin thin pylons that extended from either side of the saucer's trailing edge. The vessel that resulted from the ASDB's efforts was one of the most unusual (and some would say ugly) designs in Starfleet history. Still, U.S.S. Medusa, NX-25620 was launched in 2318 and began her shakedown soon after. Her overall dimensions were: Length, 288.33 meters; Beam, 173.89 meters; height, 74.85 meters.

Medusa performed admirably in her trials (although never quite as well as was expected by the design team) and ultimately the class was put into limited production, due to the rather limited capabilities inherent to the design and the continued proliferation of Constellation and Miranda class ships. A dozen Medusa class ships were built, many of which were retired by 2350 as the newer Niagara class ships more adequately became a true successor for the Constellation class. Some Medusa class ships were pulled from surplus yards to serve in the Dominion War. After the war, only four remained, all of which were decommissioned.

Melbourne Refit (2357)

The launch of the U.S.S. Galaxy in 2357 saw the introduction of numerous new technological advancements, and pushed the Excelsior into more of a support role in the fleet. Much as had been done with the construction of the Enterprise-A for the Constitution class, to attempt to prolong the Excelsior class's lifespan, Starfleet designed and constructed a new Excelsior class ship from a combination of leftover older and spare parts produced at the end of the production cycle. The U.S.S. Melbourne was originally contracted at Utopia Planitia as a Nebula class ship replacing an older Excelsior class ship that had already been retired, but was reallocated for the construction of the new Excelsior prototype.

The Melbourne's design included most of the technologies introduced on the Galaxy, including computer and control systems, warp drive, impulse engines, phaser banks, and torpedo launchers. The ship's computers used the latest LCARS-driven interface and command systems. The new warp drive design greatly improved stability at higher speeds and virtually eliminated the warp turbulence that the class had gained a reputation for. Impulse engines incorporated state-of-the-art small-scale driver coils that greatly improved sublight handling. As a part of a fleet-wide program for implementation on all older ships, turret phaser bank capacity was improved to rival that of the collimated phaser strip design that had become state-of-the-art on all modern Starfleet ships. In addition, the ship's interior was upgraded and crew accommodations improved, including the addition of replicators and holodeck facilities. Improved automation reduced operational crew requirements drastically, and allowed the ship to offer accommodation for families. The ship’s dimensions were the same as other standard Excelsior class ships.

U.S.S. Melbourne was launched in 2360. Unlike the Enterprise-A, the refit design was nearly a complete success, and became the template for modernization of the entire class. However, also like the Enterprise-A, the Melbourne was not built or intended for long-term duty, and a Nebula class variant replacement of the same name was planned. Command of the Melbourne was offered to the decorated William T. Riker, First Officer of the Enterprise in 2366, although Riker declined. The Melbourne was subsequently one of the ships lost at the Battle of Wolf 359 to the Borg. Some of her officers were assimilated by the Borg and sent back to Borg space in the Delta Quadrant after the battle aboard one of several assimilated Starfleet ships. Confusingly for many historians, there was a second Melbourne present that was also lost at the battle - a Nebula class replacement that was under construction which was rush-launched to meet the Borg threat.

Lakota Tactical Variant (2372)

The Lakota refit program began as a response to the Borg threat, meant to test weapons system refits originally designed for the Defiant class program. U.S.S. Lakota, NCC-42769, was already a variant of the Enterprise-B type, and had already been refit to Melbourne specifications. In her 2371 refit, Lakota was equipped with improved phasers and torpedo launchers, quantum torpedoes, and improved shields and targeting sensors. If successful, the ship would be the prototype for tactical refits to the entire class.

Unfortunately, Lakota was conscripted as part of a coup planned by Starfleet Admiral Robert Leyton. During the coup, Earth's planetary power grid was shut down, and Lakota was used as a transporter and communications relay base to deploy Starfleet security forces across the planet. Subsequently, the ship was dispatched to prevent the U.S.S. Defiant from reaching Earth and stopping the coup. The two ships each fought valiantly, with Defiant fairing only slightly better than Lakota, and ultimately Captain Erika Benteen of the Lakota stood down. Though the battle itself was monumental in preserving the freedom of the Federation, it also illustrated modern tactical deficiencies in the Excelsior design, and convinced Starfleet that it would be cheaper and simpler to produce more Defiant class ships than radically upgrade the entire Excelsior class. The Excelsior class did ultimately receive tactical upgrades of a more limited nature, though a few ships were upgraded to Lakota specifications. Lakota served valiantly in the Dominion War before being destroyed in the Second Battle of Chin'toka by Breen energy dampening weapons.